Prior work has demonstrated that same-sex relationship trajectories support the development of self-esteem in young gay and bisexual men, while opposite same-sex relationships may be associated with homonegativity. Little is known about the meaning and function of first same-sex experience in AA adolescent men and whether satisfaction with first penetrative same-sex experience impacts sexual trajectories. The goal of this project is to understand the meaning and function of first same-sex sexual experience and to prospectively be able to assess its impact on subsequent sexual experiences, young adult sexual health and health protective behaviors. The lack of representativeness of AA adolescent males in studies focused on early same-sex sexual relationships contrasted with high rates of HIV in AA adolescent MSM suggests that this project fulfills a need to understand whether these early same-sex sexual experiences impact risk for HIV. The candidate is an adolescent medicine physician with training in epidemiology. To become a successful independent minority investigator with a career focused on improving the sexual health of African American (AA) adolescent men who have sex with men (MSM), the candidate requires additional training in behavioral and cognitive theories relevant to theory including social cognitive theory of sexual development and romantic relationships, analytic techniques for integrating qualitative and quantitative data, cutting-edge methods for using technology to recruit and retain youth, and a full understanding of ethical issues associated with advocating for vulnerable adolescents. Based on past training, career goals, and commitment to a career in patient-oriented research, a K23 is the next step needed to become a successful independent minority researcher. The long-term goals of the candidate are to become an independent investigator focused on improving the sexual health (including prevention of HIV) of AA young MSM. AA MSM struggle with a sexual identity that is stigmatized in their communities, along with discrimination, and racism. As a result, first romantic and sexual experiences are likely to differ from other adolescent groups in ways that make them particularly vulnerable to HIV. The short-term goals of the candidate are to gain the skills to understand the meaning and function of first same-sex sexual experience and to be able to prospectively assess its impact on subsequent sexual experiences, sexual health and health behaviors. To attain these short- and long-term goals, training phase of the award includes 4 activities: 1) obtain knowledge of the psychological theories relevant to sexual, dating and romantic relationships in gay and bisexual adolescent males; 2) attain advanced mixed methods skills (including skills to collect and analyze qualitative data and use longitudinal data at multiple levels of analysis to assist in the interpretation of qualitative findings); 3) gain the ability to use innovative technology to recruit and retain youth; and 4) to understand the complex ethical issues involved in research with this population about sexual behavior and health. The research phase of the award is to explore the reasons for and satisfaction with first and subsequent penetrative same-sex sexual experiences (PSSE) and to examine the role of first PSSE on second and subsequent PSSEs in AA men (Study 1) and how social context impacts sexual satisfaction with first PSSE; how sexual satisfaction during first PSSE impacts time to second partner and satisfaction with second PSSE; and engagement in young adult sexual health protective behaviors during most recent sex (Study 2). Specific aim 1 is to identify the reasons for and satisfaction with first penetrative same-sex sexual experiences (PSSE) in 45 African American adolescent males in an in-depth baseline qualitative interview. In repeat qualitative and quantitative interviews over twelve months, specific aim 2 will examine the role of sexual satisfaction during first PSSE on second PSSE and subsequent same-sex sexual experiences in AA adolescent males in order to understand early same-sex sexual relationship trajectories. To aid in the interpretation of the repeat qualitative and quantitative interviews, the purpose of specific aim 3 will be to develop an internet-based survey to assess how social context impacts sexual satisfaction with first PSSE and how sexual satisfaction during first PSSE impacts time to second partner and satisfaction with second PSSE; and engagement in young adult sexual health protective behaviors during most recent sex. Upon completion of this award, the candidate will become a rigorous behavioral scientist who was informed by her clinical experience, but has the skills to successfully recruit, retain, and prospectively understand how behavior changes during sexual development in AA adolescent MSM. She will be able to understand how interpersonal and situational contexts of first same-sex sexual experiences of young AA men affect subsequent relationships and health behaviors. The findings from this work may reveal behaviors that predispose young AA MSM to high rates of HIV and may lead to an intervention that reduces sexual risk behavior in this population.